Tool for measuring the casters of axles



De. 22, 1931'. C, H. PHELPS 1,837,670

TOOL FOR MEASURING THE GASTERS OF AXLES Filed Aug. l2, 1929 2 sheets-Sheet 1 DeC- 22, 1931 c. H. PHELPS TOOL FOR MEASURING THE CASTERS OF AXLES Filed Aug. l2, 1929 2 Sheets-Sheet 2 j, lllllllllfllll/ MMI www.

Patented Dec. 22, 1931 UNITED STATES OLYDE E. rrmLPs, or ivrOUN'iv VERNON, lNew YORK, ASSIGNORQBX MESNE.[essialii?` PATENT eprice MENTS, TO HIMSELF AND'F. EVARRIGONII TOOL FOR MEASURING THE cAsmERs or AxLEs.

Application filed August 12, 19279. Seriall No. 385,353.

In order that motor vehicles may be'easily steered, it is the practice to set the frontaxles in a somewhat tilted position so that the king pins or vertical members of the spindles `car` rying the front wheels will betilted likewise longitudinally of the vehicle and the wheels caused to run in a manner similar to caster` wheels and -respond quicklyto movements of the steering gear. As long as the axle and the steering wheel spindles remain in the same position in'which they were originallyfset, the vehicle will steer easily'and will'not impose excessive strain upon theV chauffeur to maintain the wheels in the proper position and avoid shimmying -or lateral oscillation or vibration when traveling over rough roads, but after the vehicle has been in use for a considerable period' the springs frequently be-V come deformed or shift in theirl seatsupon the axle so that the caster or tilt'of the axle is changed, the result being that the *wheelsV do not run true. Itis the object of the present invention to provide a device foraccu rately measuring the caster or tilt of the a-xle and king pin so that by comparison of the same with the specifications issued by the builder -of the' particular vehicle itwill be known positively to what extent readjustment is necessary. In the case Of relatively slight shifting from the standard caster, the proper caster may be `restored by inserting wedges under the body-supporting springs but if the spring is badly deformed it will be necessary to substitute new springs. The invention is illustratedin the accompanying drawings and will Vbe hereinafter fully setA forth and defined.

lnAth'e drawings: Figure `1 is a front velevation of apparatus embodying thepresent invention, showing the Vsame arranged to determine whether or not the two axlesV of the vehicle are in the same horizontal plane, y

Fig. v2 is an elevation showing the castervmeasuring instrument in one position,

Fig.` 3 is a similar view showing a second Aposition of the tool.,

Fig. lis a top planlview,v with parts in section, all the parts being inthe position illustrated in Fig. 2,'

Fig. '5 is an enlarged sectional elevation of Vwith the tool when testing `the horizontal fset for use.: At the junction of the several arms of the base, an opening 2 is formed therethrough and a shank or posti?) has its v lower end'fit'tedin said opening and adapted to be secured .in `any convenient manner, as by theuse of a set bolt 4. Upon'the upper .end of the post 3 is swiveled `a head :5"consisting of a socket member A6 vdirectly yencir-.

clingfthe end of the post, Vand an indicator bar 7 pivoted to the side of thelsocket'mem'-` ber lat the upper extremity of r`the same. Upon the rear side of the bar?V is .secured a tubular body 8 containing a spirit "level 9, the head and the body or block f8 being the same in all essential respects as the structure disclosed :in an application for patent on a tool for measuring` `the camber of wheels, VSerial No. 298,005, filed by me August 7, 1928. Adjustably fitted upon the post is a fork 10 and acooperating fork 1l which is held to the fork 10 byan expansion spring 12 fitted about the post and operatingin .an obvious manner,'these parts being also fully shown and' described in my aforesaid application, so that Ythe present tool may be'utilized formeasuring vthe camber of wheels just as described in said application.

Itwill be noted upon referring particularif j ly to Fig. 5, that the indicator bar? and the socket member 6 are flatsided at their `point of pivotal connection andthe pivotbolt 13 has a smooth shank passing through the socket member but is threaded into the indicator bar so that the bar will be held :firmly to the socket member, and to further guard against the withdrawal of the pivot bolt a set screw 14 is inserted through the edge portion of the indicator bar and turned home against the 1o y ,pivot bolt,as clearly shown. Aspring washf er 15 isfittedaround the bolt between the head ofthe same and the socket member to bear .upon the socket member and thereby holdit in frictional. engagement with the indicator bar s that the bar will remain in any position in which it may be set. Upon referring to Figs. 2 and 3, it will be noted that the indicator bar 7 is arcuate inform and the centerlof the bar is alined radially with the pivot'bolt.. The bar is" recessed in its outer face, as shown most clearly at 16 in Fig. 5, and in the recess or chamber thusprovided there is secured a spirit level 17 also of arcu ate form and having degrees marked upon its surface,the zeropoint being at the center Jor normally high part of the arc so that, when the level is in such a position that its two ends are in the same horizontal plane, the zero point will be 'vertically over the end of the post and the bubble in the'liquid within the tube will be at zero. Upon the upper sideV of the block or body 8, at the centerof the same, a hollow post 18 is provided having a y.threaded bore, and about this post is pivotally fitted the central hub portion 19 of a straight bar 20 `which extends equal dis-v tances to the opposite sides of the hub,!a reA taining bolt 21v being engaged in the post 18 and Vaspring washer v22 being fitted` around lsaid post under the head ofthe bolt to maintain the bar in frictional engagement with the hub and the block 8 so that the bar will remain in theiposition in which it may be set. At each'end ofthe bar 20 is provided ar` ring 23 or 24 whereby the bar constitutes a transit for use in ascertaining whether the two axles of the vehicle are in the same horin axial alinement. The yinner circumference of the ring 24 is disposed concentricwith the outer circumference of the Vsame so that a ,straight bore is given said ring and extending across' the ring on its horizontal diameter Vis a hair line'or sight wire 27 which, of course, is directly alined with the sight opening 26.

On the outer circumference of each said rings, at the side remote from the indicator bar,1s a spur 28, thepurpose of which will be presentlystated.

Y Employed in connection with the transit is Va gage or sight bar A29 which has one end threaded into a socket member 3() slidably fitted upon aY post 31 rising from' a'substantial base 32.

' 'In Fig. 1, theapparatus is shown in conf nection with a front wheel 33 and a rear wheel`-34. In testing the y'easter-.of the front.

axle,` it is essential that the two axles be in the Yzontal will be noted by the Abubble inthe level 17 which may be at either same horizontal plane or it be accurately known to what extent a plane passing through the two axles varies from the horizontal. For this purpose, the parts are arranged, as shown in Fig. 1, the post 31 being disposedadjacent the rear wheel and the gage bar 29 adjusted vertically on said post until the free end of the rod may be caused to touch the-exact center ofthe hub cap 35 ofthe rear wheel; The" base 1 .and theparts carried thereby are setv adjacent the front wheel and the post 3 is adjusted vertically so that the center hub 19`ofV the bar 20 has the upper end or side of thehead of its retaining bolt alined with the center of the hub cap 36 of the front wheel. `The operator then sights through the rings 23 and 24 andV shifts the indicator bar7 about its pivot 13 until the hairline V27l registers oralines with the gage rod 29. If the two axles are in the same hori.-Y zontal plane, the bubbler in the level 17 will Abe lat the zero vpoint and the bar. 20 willbe in ahorizontal plane. If,.however, it has been necessary to shift the bar 20. pivotally in arder to impose the hairline 27 in the range of'vision between the sight opening 261 and thegage rod 29, the departure from the horipositionl ofthe side ofthe zero point, the block 8 being fixed ,tov the indicator bar 7 so that all of the parts above the pivot bolt 13 will move as an entirey ty. 1f the axles are not in the same horizontal plane, the vvariation should be noted to be subsequently deducted from the measurement acquired in testing the caster ofthe axle orking pin;V The primary test just described-having been completed, the bar 20-is set in a horizontal plane, as shown in Figs.1 and 2, and the front wheel is then shifted forvwardly about the king pin,indicated at 37 in Fig. 5until the cent-er of the hub cap 36 is in position to be engaged by the spur 28 on the ring 23, as shown in Fig. 4. The wheel is ythen swung rearwardly, as will be understood upon reference to Fig. 3, and the gage `bar 20 then swung about thepost 18 until the spur 28 upon the ring 24 touches the hub cap atl the center of the same. Inasmuch as the king pin is disposed on the samev angle or tilt as'the axle, the wheel, when-shifting from the positon shown in Figs. 2 and 4 to the position shown in Fig. 3, will also swing upwardlyeor possibly downwardly, and in order to bring the ring 24 against the hub cap it will be not only necessary to swing the barV 20 about the post 18 but to also rock the bar 7 abouty its pivot 13. VThe rocking of the bar 7 will, of course, also rock the spirit level carried by the bar and the bubble willmove to the high point of the level which may be at either side of the zero point, and the degree of inclination will denote the'degree of inclination orcaster of the axle and the king pin. By deducting the measurement noted in the first primary operation and then comparing the result With the specifications of the particular machine, it will be known to what extent the caster is amiss.

The tool is very simple in the construction and arrangement of its parts so that it may Y be produced at a loW cost. It iseasily manipulated and itrhas been found in its results.

Having thus described the invention, I claim:

1. Means for the purpose set forth comprising a support, an indicator bar pivotally mounted on the support, a level carried by the bar, a second bar mounted on the rst bar and pivoted for movement in a plane at highly efficient a right angle to the plane of movement of the first-mentioned bar, the second-mentioned bar extending equi-distantly to the opposite sides of its pivot and provided at its ends Y With means for engaging a hub cap at the Vat its ends With means for engaging a hub cap at the center of the cap when the cap with its Wheel is turned to positions at opposite sides of the center of the bar. f

3. Means for the purpose set forth comprising a post, a head pivotally mounted on l the post, a level carried by the head, a bar pivotally mounted on a side of the head and extending equal distances from its pivot to the opposite sides of the pivot and provided at its ends With spurs adapted to alternately engage a hub cap when the cap with its Wheel is turned to positions at opposite sides of the center of the bar.

In testimony whereof I aflix m signature.

'CLYDE H. PHELPg. [Ls] 

